Grinding and polishing machine.



No. 828,885. PATENTED AUG. 21, 1906.

G. G. HILL.

GRINDING AND POLISHING MACHINE.

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GRINDING AND POLISHING MACHINE.

APPLICATION FILED NOV. 19. 1904.

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No. 828,885. I PATENTED AUG. 21, 1906.

' G. G. HILL.

GRINDING AND POLISHING MACHINE.

APPLIOATION FILED NOV. 19. 1904.

4 SHEETSSHEET 3 ml 1 lllllmllllllw 'PATENTED AUG. 21, 1906.

0. G. HILL. V GRINDING AND POLISHING MACHINE.

APPLICATION FILED NOV. 19. 1904.

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CHRISTIAN t. HILL, or oH c'A'jeo; r 'nmois, isslenoaroonoruitnn B.-HILL, OFCHICAGQ ILLINOIS.

GRINDI G AND Po rsHmeHMAcHINE.

I flpecifioationfof Iletters Patent.

Iatented Aug. 21, 1906.

Applioation'flled November 19', 1904. Serial 1165233313.

To all whom it may concern: I l

Be it known that I, CHRISTIAN C. HILL, a

V citizen of the UnitedStates of America, and

a resident of Chicago, in the county of Cook and State of Illinois, haveinvented certain new -and useful Improvements in Grinding and PolishingMachines, ofwhich the following is a specification.

. p'able of ready and accurate adjustment to produce a lens or otherlike any required degree of convexity or con- "taryhorizontal section atline at a, Fig. 4is a plan view of the 'machine. Fig. 5

cavity and which is especially adapted to produce any required form ofwhat is known to optometrists as the toric lens, all as will hereinaftermore fully appear.

In the accompan drawings, Figure 1 is a front elevation 0 a grinding andpolishing machine embodying the present invention. Fig. 2 is afragmentary vertical section of the same at line a: 0:, Fig. 1.

is a fragmentary horizontal section at line a? Fig. 1. Fig. 6 is asimilar view at line at :0 Fig. 1. Fig. 7 is an enlarged detailsectional elevation at line .00 as, Fig. 8, of the lens grinding orpolishing and the lens-holding heads and their immediate connections.Fig. 8 is an end elevation of the same. Fig. 9 is a bottom view of thelenscarrying plate. Fig. 10 is a longitudinal section of. the same atline a Fig. 9. Fig. 11 is an enlarged detail sectional elevation showingthe parts in a reversed arrangement to that shown in Figs. 7 and 8; Fig..12, adiagrammatic view showing the path of movement of one grindingmember to the other. Fig. 13 is a'perspeotive view of the machine,illustrating the general arrangement of the parts.

Similar numerals of reference indicate like parts in the several views.

Referring to the drawings, 1 is the supporting frame or base of themachine, and 2 a supporting post or upright secured thereto and forminga support for the journal-brackets, which pivotally support theradius-links of the grinding and polishing headshereinafter described. 3and 4 represent a pair of substantially counterpart journal-bracketssurface having Fig. 3 is a fragmen- Fig. 2/. l

the radius-links arranged, in an lar relation to each other, as shown,and ma e vertically adjustable upon 1 the sides'of upright 1 in anyusual and suitable m'anner. The particular construction shown in thedrawings as illustrative of the adjustable connection of thejournalbrackets to'said post involves a construction as follows:

5v represents vertical undercut guide groives formed in the verticalpost aforesai 6 represents clampingbolts, the headed inner ends of whichare adapted for engagement in the guide-grooves aforesaid.

7 represents clamping-nuts screwin upon the outer ends of said bolts anda apted' to clamp the respective journal-brackets,

against the vertical post 1 at the required vertical adjustment ofsuchbrackets.

8 represents adj listing-rods arranged vertically 1n the undercutgrooves 5 aforesaid.

The up or ends of such rods are screwthreaded adjusting-nuts hereinafterescribed, while their lower portions are side ted for free verticalmovement invertica orifices formed therefor in the headed inner ends ofthe clamping-boltsfi, as illustrated in Figs. 2 and 3.

for operative engagiement with the 9 represents set-screws which screwaxi ally throu h thebolts 6 and.are adapted tobind the a justing-rods 8in, the aforesaid orifices in-the bolts 6 to effect a fixed engagementbetween said rods and said bolts. 4

10 re resents adjusting-nuts enga ingthe screw-t readed upper ends ofthe a justingrods 8 andhaving abutment upon the top surface of the mainpost or upright 1. The

said adjusting-nuts in connection with the I adjusting-rods andset-screws aforesaid constitute precision adjustments for the journal-;brackets, which in the construction shown are manually movedtoapproximately the required position, and after the engagement of thebrackets with the adj usting-rods above set forth the final andprecision adjustments are effected by the rotation of theadjustingnuts10. When so desired, scales or indexes may be provided upon the verticalfaces of the post or upright 1 for the guidance of the operator ineffecting the aforesaid adjustments of the journal-brackets 11 and 12are substantially counterpart oscillatory holdin heads or sleeves .inwhich iereinafter described are ad- ICC justably held; Such sleeves orheads are ournaled horizontally and I in angular rela tion to each otherby means of horizontal 8.1:

bors 13 and 14, fitti bearing-sleeves on the journal-brackets, as s ownmore particularly.

in Figs. 1 and 4.

15 and 16 are set-screws passing axially.

thr'oufghthe arbors 13 and 14 for-'cl'am the a oresaid-radius-bars atthe require ad justment in the holding heads or sleeves afore said.

17 and 18 represent a pair of substantially counterpart ra aforesaid andfree to oscillate upon thejouinal-axis ofsaid sleeves in paths atsubstantially right angles to each other.

19 and 20 are horizontal members on the lower ends of the radius-barsfor the-sup ort of the respective nding or polishingan the lens orwork'ho ding heads of the present construction, as hereinafter morefully set forth.

- 21 is the grinding or polishi head, and 22. the lens or Work carryinghead, oth of which various sizes of such heads may be used, :but-

more especially with a view to a reversal of such heads in cha 'ng theoperation of the machine from a pro notion of convex surfaces to theproduction of-concave Surfaces, and vice versa. In thefirst instance thelens or work holding head will be superimposed above the 'nding orpolishing head, as illustrated in igs. 1, 7, and 8, wlnle in the otherinstance the grinding or polishing head will be superimposed above thelens or work holding head, as illustrated in Fig. 1 1

23 is. a sliding bar secured to the side of the horizontal member 19 andprovided with a handled cam 24, by which its forward end is forcedagainst the side of the supporting-shank o the'head 21 to hold the samein an open-sided holding-rec formed for the same in the side of saidhorizontal member, as shown in Figs. 1 and 6, the construction be-.

ing;,adapt.ed to permit a ready removal and replacement of such head, asrequired.

25 is a clamping-screw through'one branch of the yoke-sha e forward endof the upper horizontal mem er 20 and adapted to engage against one sideof the shank of the lens or work holding head to hold the same in an oen-sided'recess formed in .the holding bloc hereinafter described, thearrangement being adapted to permit a ready removal and replacement ofsuch head, as required.

26 is a holding-block, above referred to, pivotally connected b ahorizontal bolt 27 to the other branch 0 the yoke-shaped for- Ward endof the member 20 aforesa1d,so as to be capable. of a pivotal adjustmentin a us-bars adjustable in a vert1- cal direction in the holding headsor sleeves vertical plane and carrying with it in its aid- .justment thelens or work holding head 22 sozthat the. surface of the lens operatedupon will be ground away more to one end than the other, and thus meet arequirement of he quent occurrence in spectacle-lenses, where,

owing to efective muscular convergence,'it

. is desira le-to give a prismatic form'to the lenses.

'28 is a vertical sector-shaped scale carried by the horizontal member20 for convenience in effecting the above-described adjustment of thelens or work holding head.

29 is-a horizontal segmental scale carried by the holding-block 26 inconcentric relation to; the axis of, the lens or work holding head, and30 is an index-arm carried by the shank of the head 22.. The arran ementof the parts is such that the lens orwor .holding head 22 is capable ofa pivotal adjustment in a horizontal plane, so as to adapt the principalmeridian ofa toric s ectacle-lens to a particular'astigmatic con itionof the eyes.

31 is the lensholding plate, which in the present invention is formedwith dovetail side edges adapted for engagement incorrespondingly-formed recesses in. the opposed faces of a pair ofdepending cheeks32 on the holding-head 22 aforesaid.

transverse bar 34 for the, pu ose of drawing the cheeks 32 together anclamping the same upon the dovetail edges of the lensholding plateaforesaid.

35 is a raised bearing-rid e upon the under surface of the saidlens-holding plate, preferably of the circular form shown in Fig. 9 andagainst which the back of the lens or other piece of work operated uponhas'abutment to insure its correctalinement while the cement or-likesecuring Indium is being fused inthe operation of cementing the lens tothe lensholding plate.

36 is an outer ridge upon the undersurfac of the lens-holding plate,preferably of an elliptical shape corresponding with the elliptical formof a spectacle-lens and acting as a marginal guide in setting andcementing such lens in place... 1-H r.

-37 is an annular gallery surrounding the din or polishing head 21 andhaving a d lied cm and a marginal upturned rim adapting it to containthe grinding or polishing material and tosup ly the same to the activegrinding or lis gsurfaces, as required in the norma movement oroperation of the same. In the present improvement such gallery is formedof elastic india-rubber or like material adapting it for ready removal33 represents screws passing through the cheeks 32 and screwinginto'a.

1% and at are stationary guides on the main frame. 1 having engagementwith the lower ends of the respective radius-bars 17 and 18 to preventlateral swaying of the same in actual use and maintain the same in theirpro or and respective rectilinear paths.

41 an 42ers pairs of shaftsjourna ed at right anglestoieach other on thesupporting base or frame 1 and geared together by bevelgears 43 and 4d,and a material part of the present invention consists in forming one ofsaid bevel-gears with a less number of teeth than the otherin order thata differential degree of rotation of said shafts will prevail and inthat it has been found from extended pracf tical experiment with suchprovision in conoperation of the parts e nection-with the oscillatingmovements of the respective heads 21 and22, as heretofore described,that a constant change in the point of n'din or olishing contact takesplace angllhat'a in ex tended eriod g time in the:

apses be ore the same s ot'is again reached. Fig. 12 a graphic'illustration is given of the change. ohsuch grinding or polishing spot,as formed by a ,2. encil or marker carried by the upper hea 21 upon asheetof 'aper' carried by thelower head 22, the num er of the teeth inthe bevel- ,gears 43 and 44 being twenty-four and twenty-five,respectively;

. l and 46' are counte art crank-disks carried by'the shafts 41 an42'aforesaid.

47 and 48 are adjustable wrist-pins carried by said crank-disksand-having pitman con dius-bars 11 and 18; as illustrate in Figs, 1,

nections 4:9 and 50 with the res ective rai, 5, and 6. By theindependentadjustment of said wrist-pins the grindin or polishing zone is'changedin either directlon to suit the various widths, as well as lengths, of secta cle and like lenses operated'upon, an such" -adjustment's are ofpractical value, in that speedier effects can be obtained with the oscillations of the respective heads circum tion to the other as thegrinding operation progresses. Y

- in the-:0 eration of the present invention the 'journa-bracketsare-initially "adjusted u en the vertical post or'upr" ht of the mac eby the adjusting means eretofore described and so that the activeJgrindingor polishin surface of the respective heads carried at .t elower. ends oftheradius-bars E oscillate in arcs of the radius of thelens'to he ground.

in the case of a spherical. convex orconcave lens such adjustments ofthe journalbrackets will be at a uniform height, while in the case of atoric lens the adjustment of said journal-brackets will vary to suit thetwo different curves of .thetwo meridians-toi such lens. a With theadjustment of the Journal-break. ets as above described the mechanism is{set in motion, the grinding-or polishing material.

mixed with water or other fiuidbemg-fed by hand to the 'gallery37 of thelowermost of the lens-forming heads and by. such gallery supplied to theactive grinding-surfaces of the heads, as re uired.

, Having thus fully described my said in-' vention, what I claim as'new,and, desire to. I

secure by Letters Patent, is-

' l. in a grinding or polishing machine, the combination of a support,journal-brackets attached to said supp.ort,""a pair of radiusbarsoscillating on said brackets in verticalv planes transverse to eachother, a grinding or polishinghead arranged atthe lower "end of one ofsaid radius-bars, an opposed workcar rying head arranged'at the lowerend of the otherradius-bar, and means for imparting oscillatorymovements to said radius-bars,

2, In a grinding orpolishingmachine, the combination of a support,journalbrackets attached to said support, a pair of radiusbarsoscillating on said brackets in vertical planes transverset'o'each'other, a grinding or polishing head arrangedat thelower end ofrying head arranged at'the lower end of the other radius-bar, and meansfor imparting differential oscillatory movements to said radius-bars.

3. In a grinding or polishing machine, the combination of a support,journal-brackets attached to said support, a pair of radiusbarsoscillating'on' said brackets in vertical planes transverse to eachother, "a grinding or polishing head arranged at'the lower end of one ofsaid radius-bars, an opposed work-can rying head arranged at the lowerend of the other radius oar, and means for imparting one of saidradius-bars, an'opposed work-carits oscillatory movements'to saidradius-bars,

the same comprising a pair of driving-shafts, gear connections betweensaid shafts, and means for transforming the rotary motion of said shaftsinto oscillatory-motions of the respective radius-bars.

f4. In a grinding or polishing machine, the

bars oscillating on sa'id'brackets in vertical planes'transverse to eachother, a grinding or polishing head arranged atthe'lower end of one ofsaid radius-bars,fan opposed work-fear rying head' arranged at the lowerend of the other radius-bar, and means for imparting:

cpmbination of a support, journal-brackets attached to said support, apair of radiusdifierential -oscillatory movements: to saidradius-bars,the same comprising a pair of driving-shatte gear connections betweensaid shafts having a difierent :number of teeth, and -means fortransforming the r tary motien of said shaft's into oscillatory motionsof the respective radius+bars.:

' 5. Inagrind-i-ngor polishing machine, the combination of a support,journal brackets' attachedto-saidsuppnrt, a pair of radiusbarsoseillating on said brackets :in vertical planestransverse to eachother, a grindingor polishing head arrangedat the lower end: :of one Iof said-radius bars, an-opposed-work+car+ rying head arranged at thelower end of the other radius bar, and meansfor imparting oscillatorymovements to a said radius-bars, the same'comprisi'ng a pairofdriving-shafts, gear connectionsbetween said shafts, crankdisks on saidshafts, wrist-pins on said disks, and pitman connections-betw een saidwristpins and the-respective -radius-bars.-

combination of a support, a pair of-jburnah ranged at the 6. In agrinding or polishing machine, the combination ofa support, journal-brackets attached to, said-support, a pair'- ofradius barsoscillating-on saidbrackets-in vertical planes transverse :to eachother, a grinding or polishing head arranged at the lower end -of one ofsaid radius-bars, anopposedwork+ear--v y g-head arranged" at "thelowerendof the -other radiuabar, and meansfor; imparting differentialoscillatory movements to i :said radius-bars,- the samevcomprising a par of driving shafts, gear connections? between said'shafts havingqadifferent number of teeth; -crank-disks:-on said shafts, "wrist-pinsonsaid fiisks; and :pit'manconnections betweensaid wrist-pins: and therespective radiusbars;

7. In a grinding :or polishing =machine,-the

brackets made-vertically adjustable on said support; a pairofradius-barsoscillating on saidbrackets in vertical planes transverseto each other, a grinding-or polishinghead-arranged at-the lower endef-one of said;radius-= bars, arr: opposed-work-carrying head ar-yranged at the lower end of the} -oth1erradius- 1 coinbinatien-of'asupport,"a pair ofjournalbrackets made vertically adjustable on saidsupport, a pairoi radius-barsoscillating on I rangedat a said bracketsin vertical planes transverse to eachother, a grinding or polishing headare t bar, and -means :for impartingroscillatory ranged at the lowerend-of one of said; radiusbars, anwopposed" work-carryin head are-lowerend of the other :radiusmovements to said.-radius-bars,. theesamecomprising aipair .of driving-shaftspgear cons nectronsibetweensaidshafts, and meansfor transforming. theirotary motion of said shafits'into oscillatory motions of therespectiue .ra. dius-bars;

p10. Ina-grinding.or polishingimachine,the

combination of a support, a pair of journalbrackets madeverticallyfadiustable on said sup. .ort, a pairof radius barsoscillatingxon sai brackets in vertical planes transverse-to each other;a grinding or olishing. heads arranged at the ower end 0 oneof saidradius- 'bars, an -o posed work+carrying; -headz an ranged at-telower-end-of the other radius link, and means for-imparting.diflerentialios- Y cillatorymovements to said radius-bars, the

same comprising-a pair of driving-shafts,

gearconneotions-between said shafts having a diflerent number of teetlaand means for transforming therotary-motion of said shaftsintooscillatory: motions 'ofthe respective radiusbars; a

1 1. In a grinding or polishingmachine, the combination of'a support, apair of-jorirnalbrackets made vertically adjustable. on said support, apajrofradius bars oscillating on sald brackets inverticalplanest'transverse to each otherya grinding or polishing headv arrangedat ,the lower end ofoneofsaid'radiusbars, an:=opposed-workmcarryin .headan ranged at the lowerendiof the ot er radiuslink, andimeans -for'imparting oscillatory movements to said radius-bars, thesamecomprisingapair of driving-shafts, geanconnectlons between said sha'fts,crank-disks'-on said-shafts, Wrist-pins on saiddisks, and.pit-

man 'connectionsbetween said wrist-pins and the res eotiveiradiusfbars.s

12. n a grinding or polishing machine; the combination of a support, apair of'joumalbrackets made vertically adjustableon said support, a pairof-radius-bars oscillatingion said brackets invertical planestransverse-to each other, a grindinger polishing. head-.arranged at thelower end of one ofsaid. radiuss bars, an opposed work'carryingwhead-aare ranged at the lowerend of' the other-radiuslink, and meansfor imparting differential oscillatory movements tosaid radius-bars, thesame comprising ;.a pair iof-v driving-shafts, gear connections betweensaid shafts having a diflerent. numbenof teeth, crank-disks 'on saidshafts, wrist pins on said disks, and pits man connections-between saidwrist-pins and the res ective'Tadius-bars.

13; na grinding or polishing machine, the combination of a support,journal-brackets attached to said support, a pair of radiushareoscillating on. said brackets in vertical planes transverseto eachother, a grinding or polishing head arranged at the lower end of one ofsaid radius-bars, an opposed workcarrying head 'pivotally attached tothe lower end of the other radius-bar, means for effecting a ivotaladjustment of said head in a vertical p ane, and means for imparting oscil'lator movements to said radius-bars.

14. a grinding or polishing machine, the

- combination of a support, journal-brackets attached tosaid support, apair of radiusbars oscillating on said brackets in vertical planestransverse to each other, a grindin or polishing head arranged at thelower en of one of said radius-bars, an o posed work-carrying headpivot-ally attac ed to the lower support, a pair of radius-barsoscillating on end of the other radius bar, means for effecting apivotal adjustment of said head ina vertical plane, and means forimparting diffirential oscillatory movements to said radiusars.

15." in a grinding or polishing machine, the combination of a support, aair of journal" brackets made vertically ad ustable on said sai bracketsin vertical planes transverse to each other, a grinding or polishinghead arranged at the lower end of one of said radiusbars,.an o posedwork carryin head pi-voh ally attac ed to the lower en of the otherradius-bar, means for effecting a ivotal adjustment of said head in avertic'a plane, and means; for imparting oscillatory movements to saidradius-bars.

16. In a grinding or polishing machine, the

combination of a support, a pair of journalbrackets made verticallyadjustable on said sup ort, a pair of radius-bars oscillating on saibrackets in vertical planes transverse to f each other, a grinding orpolishing head arranged at the lower end of one of said radiusbars, anopposed wo'rk-carryin head pivotally attached to the lower end 0 theother radius-bar, means for eiiecting a. pivotal adjustment of said headin a vertical plane, and

means for, imparting differential oscillatory movements to saidradius-bars."

17. in a grinding or polishing machine, the

combination of a support, journahbrachets attached to said sup ort, apair of radiusbars oscillating on said brackets, in vertical sis.

planestransverse to each other, a grinding'or polishing head arranged atthe lower end. of one of said radiuabars, an opposed work-carryingheadarranged at the lower end of the other radius-bar, means forefiecting a pivotal adjustment of said head in a horizontal plane, andmeans for imparting oscillatory movements to said radius-bars.

, 18. In a grinding or polishing machine, the

combination of a support, journal-brackets attached to said support, a.pair of radiusbarsoscillating on saidlorackets' vertical planestransverse to each otheri,.a grinding or ceases sai each other, agrinding orip'olishing' head arpolishing head arranged at the lower endof one of said radius-bars, an opposed work-car Tying head arranged atthe lower end of the other radius-bar, means for effecting a piv otaladjustment of said head in a horizontal plane, and means for impartingoscillatory movements to said radius-bars.

19. In a grinding or polishing machine, the combination of a support, apair of journal brackets made vertically adjustable on said sup ort, apair of radius-bars oscillating on sai brackets in vertical planestransverse to each other, a grinding or polishing'head arranged at thelower end'of one of said radiusbars, an o posed worlecarrying headarranged at t e lower end ofthe other radiusbar, meansfor effecting apivotal adjustment of said head in a horizontal plane, and'means forimparting oscillatory movements to said radius-bars.

"brackets made vertically adjustable on said sup ort, a pair ofradius-bars oscillating on sai brackets in vertical planes transverse toeach other, a grinding or polishing head arranged at the lower end ofone of said radiusbars, an opposed Work-carrying head arranged at thelower end of the other radiusloar, means for effecting a pivotaladjustment of said head in ahorizontal plane, and means for impartingdifierential oscillatory movements tosaid radius-bars.

21 in a grinding or polishing machine, the combination of a support,journal-brackets attached to said support, a pair of radiusbarsoscillating on said brackets in vertical planes transverse to eachother, a grinding or polishing head arranged at the lower end of planestransverse to each other, a grinding or polishing head arranged at thelower end cf one of said radius-bars, an opposed work-can rying headarranged at the lower endof the other radius-bar, means for impartingdiiier:

ential oscillatory movements to said radius 5 20. in a grinding orpolishing machine, the 'combinationof a support, a pair of journalbars,and means for efl'ecting a limited vertical adjustment of one radius-barwith rela-- tion to theother.

' '23. In a grinding or polishing machine,'the coinbinatronoi a support,a pair of journal brackets made vertically adjustable on said support, apair of radius-bars oscillating on brackets in vertical planestransverse to with relation to the other.

24. In a grinding or polishing machine, the

combination of a support, a pair otjournal brackets made verticallyadjustable on said sup ort, a pair of radius-bars oscillating on saibrackets in vertical planes transverse to each other, a grinding orpolishing head arranged at the lower end of one of said radiusbars, an oposed work-carrying head arranged at t e lower end of the otherradiusbar, means for imparting difierential oscillatory movements -tosaid radius-bars, and,

means for effecting a'limited vertical adjustment of one radius-bar withrelation to the other.

25. In a grinding or polishing machine, the

combination of a support, journal-brackets attached to said support, apair of radiusbars oscillating on said bracketsin vertical planestransverse to each other, a grinding or polishing head arranged at thelower end of one of said radius-bars, an opposed work-carrying headarranged at the lower end of the other radius-bar, means for impartingoscillatory movements to said radius-bars, and means for guiding thelower ends of the radiusbars in rectilinear paths.

26. In a grinding or polishing machine, the combination of a support,journal-brackets attached to said support, a pair of radius.- barsoscillating on said brackets in vertical planes transverse to eachother, a grinding or polishing head arranged at the lower end of one ofsaid radius-bars, an opposed Work-carrying head arranged at the lowerend of the other radius-bar, means for imparting differ entialoscillatory movements to said radiusbars, and means for guiding thelower ends of the radius-bars in rectilinear paths.

- 27. In a grinding or polishing machine, the

. combination of a support, a pair-of journalbrackets made verticallyadjustable on said support, a pair of radius-bars oscillating on saibrackets in vertical planes transverse to each other, a grinding orpolishing head arranged at the lower end of one of said radiusbars, an oposed work-carrying head arranged at t e lower end of the otherradiusbar, means for imparting oscillatory movements to saidradius-bars, and means for guid ng the lower ends of the radius-bars in:rectilinear paths.

' 28. In a grinding or polishing machine, the combination of a su port,a pair of .journalbrackets made vertically adjustable on said support, apair of radius-bars'oscillating onsai brackets in vertical planestransverse toeach other, a grinding or-polishing head arranged at thelower end of one of saidiradiusbar, means for imparting difierentialoscillatory movements to sald-radius-bars, and.-

means for guidin the lower ends of the radius-links in recti inearpaths.-

29. In a grinding or polishing machine of I the character hereindescribed, the combination of a work-holding head, and a work-car ryingpla/te provided with a bearing-ridge on its face.

.30. In a grinding or polishing machine of "the character hereindescribed, the combination of a work-holding head, and awork-carryinghead provided with a bearing-ridge and an annular guiding-ridge on' itsface.

31. In a grinding or polishing machine of the character hereindescribed, the combination of a work-holdin head, side cheeks onsaidhead having beve ed recesses in their opposed ,faces, awork-carrying plate ha eveled edges, and means for-c amping sai cheeksupon the beveled edges of said plate.

32. In a grinding orpolishing machme of the character herein described,the combination of a work-holding head, side cheeks on said head havingbeveled recesses in their oposed faces, a work-carrying plate havineveled edges, and means for c amping sai cheeks upon the beveled edgesof said plate, the same comprising screws passing through said cheeks,and a transverse bar receiving said screws.

33. In a grinding or polishing machine of the character hereindescribed, the combination with the grinding or polishing andworkholding heads arranged in apposition, of a gallery secured to thelowermost head in a plane with the upper surface of'said head and rprovided with an upturned margin.

34. a grinding or polishing machineof the character herein described,the combination with the grinding or polishing and workelastic gallerysecured to the lowermost head in a plane with the upper surface of saidhead and providedwith an u turned margin and a reinforced annular e'olar.

36. In a grinding or polishing machine, the hombination of agrinding-head, a work-holding head, and means for imparting difierentialreciprocation to said heads in directions transverse to each other, thesame comprising a pair of driving-shafts, gear connections between saidshafts having a different number of teeth, and means fortransforniingthe otary motion of said'shafts intoreciprocatfl mg motions of saidheads.

pitrnan connections between said crank-disks 37. In a grinding orpolishing machine, the combination of a grindlng-head, a. Work-holdinghead, and means for imparting diflerential reciprocation to said headsin directions transverse to each other, the same comprising a pair ofdriving-shafts, gear connections Witnesses: between said shafts having adifferent num- ROBERT BURNS, ber of teeth, crank-disks on said shafts,and M. H. HOLMES.

Signed at Chicago, Illinois, this 14th day of November, 1904.

' CHRISTIAN C. HILL.

and the respective heads. 10

